The students that come from outside of the city, stay alone without parental presence and direct supervision. The dynamic and variation of culture, rapid flow of information, and accessible information source contribute to increasing of the knowledge, attitude, and behavior of teenagers, either with the positive or negative tendency. The objective was assess teenager’s attitude in religion-based private high school in Yogyakarta used an analytic observational study with cross sectional design. The population and sample of this research were high school students in religion-based private school in Yogyakarta. The sample was selected by proportional stratified random sampling method. The results were analyzed using univariate and bivariate analysis. Bullying, truancy, school tardiness, dating, unwanted pregnancies, brawls/fights, gang students, poor manners, smoking, and pornography were the negative attitudes found in the subject of this research. About 45,3% of them had a bad attitude and 33,7% of them had a bad attitude. Several approaches for example, asking the commitment from a certain organization which concerns on mentoring and coaching of students, cooperation with student parents, and make the school environment more pleasant.